In general, a wire harness is an electric wiring system containing a number of cables, often comprising as many as 400-500 circuits. When producing such large scale wire harnesses, a plurality of unit cable binding assemblies (called temporary binding circuits) is first manufactured. These are then electrically connected by various means by what is called the final binding process.
The temporary binding circuit contains last-in terminals which are fastened to the ends of a plurality of cables comprising the wire harness and are mounted onto a connector at the final binding of the temporary binding circuits or when connecting the wire harness to a desired device (the last-in process). In other words, this last-in terminal is left exposed on the end of the cable until the last-in process is carried out.
The existence of the last-in terminal creates various problems in manufacturing wire harnesses; e.g. its susceptibility to deformation during transport. Obviously, if the terminal is deformed, mounting on a connector becomes difficult, continuity of the cable may be compromised, etc. Similarly, there is a tendency of cable components fastened to the last-in terminal to become entangled with other cable components, thus making handling difficult.
Also, the last-in process is labor intensive; i.e. there are many cases wherein a plurality of last-in terminals is connected to a common connector. In such cases, cables connected to the last-in terminal which had been previously inserted prevented the last-in terminals of succeeding temporary binding circuits from being inserted. In energizing each cable of the temporary binding circuits, the terminals on the cables are inserted into a female housing in advance, and then connected to the joint connector.
Since the operation is carried out manually, a problem arises in making certain that each last-in terminal is inserted into its proper connector. Particularly in view of the large number of binding circuits which are often present, this can be a serious problem and a cause of rejection of completed harnesses. A further problem resides in testing the continuity of the individual circuits. Such tests require that the terminal be mounted on a connector in a specified position. However, before the last-in process is completed, the terminal has not yet been mounted. Therefore, carrying out the continuity test to determine the integrity of the circuit is extremely difficult.